JPH0760770A - Frp solid molding method - Google Patents

Abstract

PURPOSE:To obtain effects such as simplification of molding operation and a cost reduction even in the case where an end part of a prepreg is pressed by the surface of a tool and it is difficult to make the prepreg into a solid form, by a method wherein a jig having a fixed height is arranged between an end part of an FRP prepreg and an end part of a rubber sheet and a vacuum is drawn. CONSTITUTION:In an FRP solid molding method, a core material 5 having a desirous form is installed on a tool face 3, an FRP prepreg 2 and rubber sheet 1 are arranged so that the core material 5 is coated with them and since vacuum drawing of the inside of the rubber sheet 1 is performed, the FRP prepreg 2 is stuck to the core material 5 and an FRP solid molded matte having a form coincides with the core material 5 is obtained. Then a jig 6 having a fixed height is arranged between an end part of the FRP prepreg 2 and an end part of the rubber sheet 1 and the vacuum drawing 4 is performed. The circumference of the rubber sheet 1 is raised like this and since sticking timing is delayed, the end part of the prepreg 2 can be prevented from being stuck to the tool face 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional molding method of FRP (fiber reinforced plastic).

[0002]

2. Description of the Related Art Conventional methods for stacking sheet-like FRP prepregs (hereinafter abbreviated as prepregs) to obtain a three-dimensional shape include a method of manually pressing one by one to adjust the shape, and work efficiency. Figure 5
There is a method shown in. In this method, a required number of prepregs 2 are placed on a core material 5 having a required shape on the tool surface 3, and finally a rubber sheet 1 is covered to seal the periphery, and the rubber sheet 1 is adhered by vacuuming 4. This is a method for obtaining the required shape.

[0003]

According to the conventional method described with reference to FIG. 5, as shown in FIG. 6, the end portion (A portion) of the prepreg 2 is moved to the tool surface 3 by vacuum drawing from the vacuum drawing hole 4 depending on the shape. It is pressed down first and becomes immovable, and it is possible to prevent the entire prepreg 2 from sticking to part B of the core material 5,
In some cases, the shape corresponding to the shape of the core material 5 may not be obtained, or the product may have defects. Therefore, the method utilizing vacuum evacuation has a fairly limited application range.

In view of the above-mentioned state of the art, the present invention is to provide a three-dimensional molding method of FRP which does not cause the problems as in the conventional method.

[0005]

According to the present invention, (1) a core material having a desired shape is installed on a tool surface, an FRP prepreg and a rubber sheet are sequentially arranged so as to cover the core material, and the rubber sheet is provided. A method for obtaining an FRP three-dimensional molded article having a shape conforming to the core material by bringing the FRP prepreg into close contact with the core material by vacuuming the inside, and between the end portion of the FRP prepreg and the end portion of the rubber sheet. The FRP three-dimensional molding method is characterized in that a jig having a constant height is arranged and a vacuum is drawn. (2) The FRP three-dimensional molding method according to the above (1), wherein a jig having a variable height, which is made of a spring, a stretchable material or a retractable device, is used instead of the jig having a constant height. (3) The FRP three-dimensional molding method according to the above (1) or (2), characterized in that heating is applied simultaneously with evacuation.
Is.

That is, according to the present invention, a jig is arranged inside a rubber sheet, and vacuuming is started in a state where the rubber sheet is first floated, thereby delaying the time when the end of the prepreg comes into close contact with the tool surface. Completely adheres to the core material to form a desired molded body.

The jig used in the present invention is generally made of a rigid material such as metal having a fixed height, but a jig whose height changes, for example, a spring, a jig made of a stretchable material, A formula tool or the like can also be used.

According to only evacuation, when the movement of the prepreg is bad, it is preferable to perform heating in combination with the above jig. The heating is set to a temperature at which the resin viscosity is appropriately lowered within a temperature / time range where curing of the prepreg does not proceed so much. The prepreg is cured by heating it to the curing temperature after molding the prepreg or placing it in an apparatus such as an autoclave to heat and cure it.

The present invention can be advantageously applied to the three-dimensional molding of FRP made of a thermosetting resin such as epoxy resin or phenol resin reinforced with carbon fiber, aramid fiber, glass fiber or the like.

[0010]

When the inside of the rubber sheet is evacuated, the prepreg is first brought into close contact with the convex portion of the core material by being pressurized from the outside of the rubber sheet by the atmospheric pressure. If the circumference of the rubber sheet is low, the periphery of the rubber sheet will also adhere to the tool surface, and then the prepreg will also adhere to the tool surface, preventing it from adhering to the core material. By delaying the time when the rubber sheet adheres to the tool surface, it is possible to prevent the end of the prepreg from adhering to the tool surface until the prepreg conforms to the shape of the core material.

Further, when heating is also used, the viscosity of the resin is lowered, the sliding of the prepreg on the tool surface is improved, and the prepreg itself becomes soft, so that the shape of the core material is easily adapted.

[0012]

EXAMPLE An example of forming a hat type stringer with a stringer required for a composite reinforced outer plate of an aircraft will be described below.

(Embodiment 1) This embodiment will be described with reference to FIG. In FIG. 1, 1 is a silicone rubber sheet, 2
Is an FR made of epoxy resin reinforced with carbon fiber
A prepreg of P, 3 is a tool surface, 4 is a vacuum hole, 5 is a core material having a trapezoidal cross section with a base angle of 45 ° and a height of 18 mm, and 6 is a metal jig having a rectangular cross section with a height of 18 mm. As shown in FIG. 1, each member was placed on the tool surface 3, vacuumed through the vacuum holes 4, the pressure inside the silicone rubber sheet was -650 mmHg, and heating to 50 ° C. was performed. The prepreg 2 could be adhered to the part corresponding to the side surface of the core material 5 without any gap.

(Embodiment 2) Instead of the jig 6 of the above Embodiment 1, a spring 7 is used as shown in FIG. 2, and the silicon rubber sheet 1 is left in a floating state before evacuation, and evacuation is performed. After that, when the silicone rubber sheet 1 was lowered to the vicinity of the tool surface 3 and the same procedure as in Example 1 was performed, the same results as in Example 1 were obtained. Further, instead of the spring 7 of this embodiment, a stretchable jig (sponge-like one) 8 as shown in FIG. 3 and a retractable jig 9 as shown in FIG. Even if the same result was obtained.

[0015]

According to the present invention, by controlling the timing at which the rubber sheet comes into close contact with the tool surface, the vacuum can be maintained even when it has been difficult to form a three-dimensional shape by pressing the prepreg end portion against the tool surface. The three-dimensional shaping method used can be applied, and the effects of simplifying the molding work and reducing the cost can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment using a jig having a constant height according to the present invention.

FIG. 2 is an explanatory view of an embodiment using the spring of the present invention as a jig.

FIG. 3 is an explanatory diagram of an example in which the stretchable material of the present invention is used as a jig.

FIG. 4 is an explanatory diagram of an embodiment in which the folding instrument of the present invention is used as a jig.

FIG. 5 is an explanatory view of one aspect of conventional three-dimensional molding of a prepreg using vacuum.

FIG. 6 is an explanatory diagram showing the problems of the conventional method.

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Claims (3)

[Claims] 1. A core material having a desired shape is installed on a tool surface, an FRP prepreg and a rubber sheet are sequentially arranged so as to cover the core material, and the inside of the rubber sheet is evacuated to vacuum the core material. In the method for obtaining an FRP three-dimensional molded article having a shape conforming to the core material by closely contacting the FRP prepreg with the above, a jig having a constant height is provided between the end of the FRP prepreg and the end of the rubber sheet. The FRP solid molding method is characterized by performing vacuuming. 2. The FRP three-dimensional molding method according to claim 1, wherein a jig having a variable height, which is made of a spring, a stretchable material, or a retractable device, is used instead of the jig having a constant height. . 3. The FRP three-dimensional molding method according to claim 1, wherein heating is applied simultaneously with the evacuation.